1. Field of the Invention
The technical scope of the invention is that of launching devices enabling sub-caliber artillery projectiles to be fired from a gun barrel.
2. Description of the Related Art
So as to improve the range of large caliber artillery projectiles, it is possible to employ projectiles that have lift surfaces such as fins and to combine such means with the sub-calibration of the projectile so as to reduce its aerodynamic drag.
These solutions firstly require the use of uncoupling means between the projectile and the weapon so that the spin effect created by the gun barrel does not damage the projectile fins and secondly the use of means to compensate for the difference in caliber between the projectile and the barrel.
Upon exiting the barrel, these means having performed their functions, it is necessary for them to be discarded from the projectile without this hindering or perturbing the projectile's trajectory.
For this, it is known by document EP-0905473 to employ a sliding band around a base pushing the projectile. This base is separated from the projectile by means of a small pyrotechnic ejector. Independently from the ejection of the base, the caliber compensation means, also called sabot sectors, placed to the fore of the projectile are distanced from the projectile by the dynamic air pressure.
The solution using the pyrotechnic ejector is complicated since firing must be performed precisely and reliably. The impulsion of the ejector can perturb the projectile's trajectory if this impulsion is not perfectly coaxial to the trajectory. Furthermore, retaining the sabot sectors on the projectile requires machining to be performed on the projectile to be able to install pins that are sectioned upon firing. These pins need to be precisely calibrated for fracture.
Medium-caliber sub-caliber projectiles are known that incorporate a sabot integral with a base and which opens upon exiting the gun barrel through the effect of the centrifugal force. Such projectiles are disclosed, for example, by U.S. Pat. No. 4,419,796, DE-1262830 and U.S. Pat. No. 4,476,785.
These sabots are generally integral with the base and incorporate incipient fractures to facilitate the release of the projectile. Such solutions cannot be transposed to an artillery projectile whose spin is reduced by the effect of the sliding band.
A medium-caliber dart-type projectile is also known by patent WO93/02333 that is released by a sabot integral with a base. The solution proposed implements an embrittled hinge that fractures upon exiting the gun barrel. Such a solution is likely to perturb the trajectory of an artillery projectile.
Patent GB-123501 succinctly describes a sub-caliber projectile of large caliber (406 mm) wherein its sabot sectors are hinged to the base. These hinges are opened through the action of the centrifugal force. However, these hinges are not clearly defined by this patent. These hinges enable the base to be pushed rearwards out of the way of the projectile. It even seems that the sectors remain integral with the base by their hinges as suggested in FIG. 3.
This solution can not be transposed to an artillery projectile equipped with a sliding band and for which the centrifugal force is reduced and for which there is a high risk of perturbation of the projectile's flight linked to dissymmetry in opening the sabot segments.